DTC 0413

Front Heated Oxygen Sensors (0409: Right Bank) (0413: Left Bank)

COMPONENT DESCRIPTION
The front heated oxygen sensor is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The front heated oxygen sensor has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The front heated oxygen sensor signal is sent to the ECM. The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.

ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values, and are measured between each terminal and (25) (ECCS ground).

ON BOARD DIAGNOSIS LOGIC
To judge the malfunction of front heated oxygen sensor, this diagnosis measures front heated oxygen sensor cycling time. The time is compensated by engine operating (speed and load), fuel feedback control constant, and front heated oxygen sensor temperature index. Judgment is based on whether the compensated time (front heated oxygen sensor cycling time index) is inordinately long or not.

DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has just been completed, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.

TESTING CONDITION:
Always perform at a temperature of more than -10°C (14°F).

Before performing following procedure, confirm that battery voltage is more than liv at idle.

Never raise engine speed above 3,600 rpm (A/T), 4,000 rpm (M/T) during the "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE". If the engine speed limit is exceeded, retry the procedure from step 2).

OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the front heated oxygen sensor circuit. During this check, a 1st trip DTC might not be confirmed.

Without TOOLS
(1) Start engine and warm it up to normal operating temperature.
(2) Set voltmeter probes between ECM terminal (50) RH, (51) LH (sensor signal) and (25) (ECM ground).
(3) Check the following with engine speed held at 2,000 rpm constant under no load.
- Malfunction indicator lamp goes on more than 5 times within 10 seconds in Diagnostic Test Mode II (FRONT HEATED OXYGEN SENSOR MONITOR).

Electrical Diagrams/Left Bank

Circuit Connectors/Left Bank

Electrical Diagrams/Right Bank

Circuit Connectors/Right Bank

1 Of 2:

2 Of 2:

DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
Front heated oxygen sensor heater

Check resistance between terminals (3) and (1).

Resistance: 2.3 - 4.3 Ohms at 25°C (77°F)

Check continuity between terminals (2) and (1), (3) and (2).

Continuity should not exist.

If NG, replace the front heated oxygen sensor.

CAUTION: Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.